Semiconductor Device, Radio Communication Terminal Using the Same, and Control Method

ABSTRACT

A communication terminal according to one aspect of the present invention includes a baseband LSI that performs baseband processing for communication, an application LSI that includes a vocoder function and performs processing according to an application, an audio LSI that performs one of D/A conversion and A/D conversion on audio data, and a switch circuit that is installed in the application LSI and connects a data path between the audio processor LSI and the baseband LSI.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese patent application No. 2011-187039, filed on Aug. 30, 2011, thedisclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

The present invention relates to a semiconductor device, a radiocommunication terminal using the semiconductor device, and a controlmethod.

In recent years, communication terminals using vocoders (vocoders) havebeen used. For example, in Japanese Unexamined Patent ApplicationPublication No. 2000-148582, vocoders having different rates areswitched to be used according to the state of lines.

The inventors of this application have found various problems to besolved in the development of semiconductor devices used forcommunication terminals and the like. Each embodiment disclosed in thisapplication provides, for example, a semiconductor device suitable for acommunication terminal and the like. More detailed features will beobvious from descriptions of this specification and attached drawings.

SUMMARY

An aspect disclosed in this specification includes a semiconductordevice, and the semiconductor device is used as an application processorunit in a communication terminal.

According to the present invention, it is possible to provide anexcellent semiconductor device, a communication terminal, and a controlmethod of the communication terminal.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, advantages and features will be moreapparent from the following description of certain embodiments taken inconjunction with the accompanying drawings, in which:

FIG. 1A is an external view showing a configuration example of a radiocommunication terminal 500;

FIG. 1B is an external view showing a configuration example of the radiocommunication terminal 500;

FIG. 2 is a block diagram showing a configuration example of anelectronic device 600 according to a first embodiment;

FIG. 3 is a block diagram showing a configuration of an electronicdevice according to a method 1;

FIG. 4 is a block diagram showing a configuration of an electronicdevice according to a method 2;

FIG. 5 is a diagram showing a data flow of the electronic deviceaccording to the method 1;

FIG. 6 is a diagram showing a data flow of the electronic deviceaccording to the method 2;

FIG. 7 is a block diagram showing a configuration example of anapplication LSI mounted on an electronic device;

FIG. 8 is a diagram showing data paths among a baseband LSI, anapplication LSI, and an audio LSI;

FIG. 9 is a diagram showing data paths among the baseband LSI, theapplication LSI, and the audio LSI;

FIG. 10 is a diagram showing data paths among the baseband LSI, theapplication LSI, and the audio LSI;

FIG. 11 is a diagram schematically showing data flow and power supply inan application LSI 601;

FIG. 12 is a diagram schematically showing data flow and power supply inthe application LSI 601;

FIG. 13 is a diagram schematically showing data flow and power supply inthe application LSI 601; and

FIG. 14 is a diagram schematically showing a configuration example of amute circuit.

DETAILED DESCRIPTION First Embodiment

Specific embodiments to which the present invention is applied areexplained hereinafter in detail with reference to the drawings. However,the present invention is not limited to the embodiments shown below.Further, the following descriptions and the drawings are simplified asappropriate for clarifying the explanation.

First, with reference to FIGS. 1A, and 1B, an outline of a radiocommunication terminal, which is a preferable electronic device to whicha semiconductor device according to this embodiment is applied, isexplained. FIGS. 1A and 1B are external views showing a configurationexample of a radio communication terminal 500. Note that theconfiguration example shown in FIGS. 1A, 1B and 2 shows a case where theradio communication terminal 500 is a folding-type mobile phoneterminal. However, the radio communication terminal 500 may be otherradio communication terminals such as a smart phone, a potable gameterminal, a tablet PC (Personal Computer), and a laptop PC. Further,needless to say, the semiconductor device according to this embodimentmay also be applied to devices other than the radio communicationterminals.

FIG. 1A shows a closed state (folded state) of the radio communicationterminal 500 which is a folding-type mobile phone terminal. FIG. 1Bshows an opened state of the radio communication terminal 500. The radiocommunication terminal 500 has such a structure that a first housing 501is connected to a second housing 502 through a hinge 503. In the exampleshown in FIGS. 1A and 1B, a plurality of buttons are arranged on thefirst housing 501. Meanwhile, the second housing 502 includes twodisplay devices 20A and 30A and two camera devices 20B and 30B. Each ofthe display devices 20A and 30A is an LCD (Liquid Crystal Display), anOLED (Organic Light-Emitting Diode) display, or the like.

The display device 20A is disposed in such a manner that its displaysurface is positioned on the inside main surface (front surface) of thesecond housing 502. That is, the display device 20A is a main displaythat is viewed by a user when the user operates the radio communicationterminal 500 in an opened state. On the other hand, the display device30A is a sub display that is disposed in such a manner that its displaysurface is positioned on the outside main surface (rear surface) of thesecond housing 502.

The camera device 20B is a main camera that is disposed in such a mannerthat its lens unit is positioned on the outside main surface (rearsurface) of the second housing 502. On the other hand, the camera device30B is a sub camera that is disposed in such a manner that its lens unitis positioned on the inside main surface (front surface) of the secondhousing 502.

Next, with reference to FIG. 2, a configuration of an electronic device600 in which a semiconductor device according to the present inventionis installed is explained. FIG. 2 is a block diagram showing aconfiguration example of the electronic device 600 according to a firstembodiment of the present invention. The electronic device 600 isinstalled, for example, inside the radio communication terminal 500shown in FIGS. 1 and 1B. As shown in FIG. 2, the electronic device 600includes an application LSI (Large Scale Integration) 601, a basebandLSI 602, an RF (Radio Frequency) subsystem 603, a battery 605, a powerIC (Integrated Circuit) 606, an LCD 607, an operation input unit 609, anaudio LSI 610, a microphone 611, a speaker 612, and a card IF(Interface) 608. These elements are mounted on a board 630.

The application LSI 601 includes a processor unit that performsprocessing of reading out a program stored in a memory 604 (not shown inFIG. 2) to implement various functions of the electronic device 600. Forexample, the application LSI 601 executes an OS (Operating System)program obtained from the memory and also executes application programsthat are executed on this OS program. Note that the memory storesprograms and data that are used by the application LSI 601. Further, thememory includes a non-volatile memory which retains stored data evenwhen the power supply is cut off and a volatile memory in which storeddata is cleared when the power supply is cut off.

The baseband LSI 602 includes a processor unit that performs basebandprocessing. For example, the baseband LSI 602 performs an encodingprocess (e.g., error correction coding such as convolution coding andturbo coding) or a decoding process for data to be transmitted/receivedby the electronic terminal 600. More specifically, the baseband LSI 602receives transmission data from the application LSI 601, performs anencoding process for the received transmission data, and transmits theencoded transmission data to the RF subsystem 603. Further, the basebandLSI 602 receives reception data from the RF subsystem 603, performs adecoding process for the received reception data, and transmits thedecoded reception data to the application LSI 601.

The RF subsystem 603 performs a modulation process or a demodulationprocess for data to be transmitted/received by the electronic device600. More specifically, the RF subsystem 603 generates a transmissionsignal by modulating transmission data received from the baseband LSI602 by a carrier wave, and outputs the transmission signal through anantenna. Further, the RF subsystem 603 receives a reception signalthrough an antenna, generates reception data by demodulating thereception signal by a carrier wave, and transmits the reception data tothe baseband LSI 602.

The battery 605 is an electric battery and is used when the electronicdevice 600 operates without using any external power supply. Note thatthe electronic device 600 may use the battery 605 even when the externalpower supply is connected. Further, it is preferable that a secondarybattery is used as the battery 605.

The power IC 606 is a power management IC that generates an internalpower supply from the battery 605 or the external power supply. Thisinternal power supply is supplied to each block of the electronic device600. Note that the power IC 606 controls the voltage of the internalpower supply for each of the blocks that receive the internal powersupply. The power IC 606 controls the voltage of the internal powersupply under instructions from the application LSI 601. Further, thepower IC 606 can also control whether the internal power supply issupplied or cut off for each of the blocks. Further, when the externalpower supply is supplied, the power IC 606 controls the charging to thebattery 605.

The LCD 607 is, for example, a display device, and displays variousimages according to the process performed in the application LSI 601.The images displayed in the LCD 607 include user interface imagesthrough which a user gives instructions to the electronic device 600,camera images, moving images, and the like. As a matter of course,display devices other than the LCD 607 may be used instead.

The operation input unit 609 is a user interface which is operated by auser and through which the user gives instructions to the electronicdevice 600. While key buttons are shown as an example of the operationinput unit 609, a touch panel may be used instead. The audio LSI 610 isan audio processor unit that decodes audio data transmitted from theapplication LSI 601 to drive the speaker 612, and encodes audioinformation obtained from the microphone 611 to generate the audio data,to output the audio data to the application LSI 601. Thus, the audio LSI610 is a processor unit that includes a D/A converter and an A/Dconverter. Lines to connect the aforementioned configurations are formedin the board 630.

Next, problems in the vocoder system that are found as a result of studyby the inventors will be described. It should be noted that the term“vocoder” is used to collectively indicate processing includingdecoder/encoder for telephone call in a communication terminal. Inshort, the vocoder is a technique of audio processing, and aims toexecute encoding of compressed data such as AMR and decoding of PCMdata. The vocoder is required for performing voice call, reproduction ofvoice guidance, and recording. In the vocoder system, a C-vocoder systemin which the baseband LSI 602 executes elements required for the vocoderis used. Further, the C-vocoder system includes two methods of a methodof executing elements (telephone call, recording, guidance reproduction,and the like) required for the vocoder only by the baseband LSI 602 asshown in FIG. 3 (hereinafter referred to as a method 1) and a method ofexecuting a part of the elements required for the vocoder by thebaseband LSI 602 as shown in FIG. 4 (hereinafter referred to as a method2).

In the method 1 shown in FIG. 3, the baseband LSI 602 executes all theaudio data processing. Specifically, the baseband LSI 602 extracts data(e.g., AMR data) required for voice call from the reception datademodulated by the RF subsystem 603, to decode the extracted data to thePCM data. The baseband LSI 602 outputs the PCM data to the audio LSI610. The audio LSI 610 converts the PCM data into the analog signal, toallow voice to be reproduced from the speaker 612 (Down Link). Note thatthe AMR data is compressed data, and the PCM data is non-compresseddata.

On the other hand, the audio LSI 610 performs A/D conversion on theanalog signal of the voice detected by the microphone 611 to generatethe PCM data. The audio LSI 610 outputs the PCM data to the baseband LSI602. The baseband LSI 602 encodes the PCM data to the form such as AMRto convert the form into a form that allows the RF subsystem 603 toreceive the data. For example, the baseband LSI 602 adds informationrequired for the radio communication to output the information to the RFsubsystem 603. Then the RF subsystem 603 modulates the signal and sendsthe modulated signal to Air from the antenna (Up Link). In this way,transmission processing for voice call is performed. In addition, thebaseband LSI 602 executes effect processing on the PCM data, andguidance reproduction, memo recording and the like that do not involvecommunication.

According to the method 1, as shown in FIG. 5, data regarding audioprocessing (in FIG. 5, DLDATA, ULDATA, SYNC, CLK, and hereinafterreferred to as audio processing data) is transmitted between thebaseband LSI 602 and the audio LSI 610. FIG. 5 is a diagramschematically showing a data flow of the audio processing data.Accordingly, terminals of the baseband LSI 602 and terminals of theaudio LSI 610 are directly connected through the lines on the board 630.

Incidentally, there is a request to cause the application LSI 601 toexecute elements of the vocoder. In particular, voice quality isexpected to be improved in the LTE (Long Term Evolution) by causing theapplication LSI 601 to execute the elements of the vocoder. In thiscase, as shown in the method 2 in FIG. 4, such a configuration isemployed in which the application LSI 601 is mounted on the board 630.In the C-vocoder according to the method 2, such a configuration may beemployed in which a part of the elements (e.g., guidance reproduction,recording) of the vocoder is performed by the application LSI 601, andthe rest of the elements (e.g., voice call) are performed by thebaseband LSI 602. Note that the LTE is a communication standardspecified by the 3GPP standards body.

In the method 2, as is different from FIG. 2, lines connecting thebaseband LSI 602 and the audio LSI 610 are formed on the board 630. Inshort, in FIG. 2, while the lines from the application LSI 601 to thebaseband LSI 602 and the lines from the application LSI 601 to the audioLSI 610 are formed, lines that directly connect the baseband LSI 602 andthe audio LSI 610 are not formed. Meanwhile, in FIG. 4, lines thatdirectly connect the baseband LSI 602 and the audio LSI 610 are formedon the board 630.

FIG. 6 shows a data flow of the audio processing data according to themethod 2 shown in FIG. 4. FIG. 6 is a diagram schematically showing thedata flow when guidance is reproduced, for example. In the method 2, theaudio LSI 610 is required to transmit the audio processing data to theapplication LSI 601 or the baseband LSI 602. When the guidancereproduction or recording is performed, the application LSI 601 executesvocoding. In this case, the audio processing data from the audio LSI 610is transmitted to the application LSI 601. On the other hand, when thevoice call is performed, the baseband LSI 602 executes vocoding. In thiscase, the audio processing data from the audio LSI 610 is directlytransmitted to the baseband LSI 602. In this case, the data flow is thesame to that shown in FIG. 5. A data flow in which the audio processingdata is directly transmitted between the baseband LSI 602 and the audioLSI 610 and a data flow in which the audio processing data istransmitted through the processing in the application LSI 601 are mixedin one electronic device 600.

The inventors of the present application consider that the data flowfrom the baseband LSI 602 is required to be switched from theapplication LSI 601 to the audio LSI 610 when the application LSI 601executes a part of the elements of the vocoder. In short, it is requiredto provide a component to connect lines from the baseband LSI 602 to theaudio LSI 610 and the application LSI 601, and to switch the path on theboard 630. In other words, one example to switch the path may be amethod of providing a switch circuit on the board to switch the dataflow between the baseband LSI 602 and the application LSI 601 and thedata flow between the baseband LSI 602 and the audio LSI 610. Then, itis possible to switch data flow according to the control signal fromPort of the application LSI 601. This is because there is no need tore-design the application LSI 601, which allows easier manufacturing.

In order to achieve higher functionality and to further improve quality,employment of an A-vocoder is desired in which the application LSI 601executes all the digital processing (decoding to PCM data, encoding toAMR data, noise canceller, echo canceller, SRC processing, improvementin voice quality and the like) except packet separation from the RFsubsystem 603 among the processing in the telephone call, to outputfinal audio data to the audio LSI 610. In particular, it is expectedthat, in the LET generation, the voice call is also regarded as oneapplication, and the vocoder is more likely to be treated as a part ofthe application. It is expected that transition from the C-vocodersystem to the A-vocoder system will gradually advance in order toimprove quality of voice call. It is also considered that, in thetransition period from the current C-vocoder system to the A-vocodersystem, both of the C-vocoder system and the A-vocoder system will beused. In short, it is required to determine which system to employaccording to the manufacturer of communication terminals and the type ofthe communication terminal.

Incidentally, there is a demand to commonly use the board 630 in varioustypes of communication terminals, in particular mobile phones. In short,it is desired to achieve the configuration in which both of theA-vocoder and the C-vocoder can be achieved on one board. However, it isdifficult to commonly use the board both in the A-vocoder system and theC-vocoder system of the method 2. For example, since it is required tominimize the size of each equipment, the mounting rate in a board hasbeen maximally enhanced. Accordingly, it may be difficult to secure thespace to additionally mount the switch circuit in some systems, whichmay require another board. In other words, when the board is commonlyused in the A-vocoder system and the C-vocoder system, the switchcircuit required for the C-vocoder system is not required in theA-vocoder system, which imposes strict restrictions on the design.

In order to solve the problem stated above, the inventors of thisapplication have found a configuration to commonly use the board in asimple manner. This configuration will be described hereinafter indetail. First, FIG. 7 shows a configuration example of the applicationLSI 601 according to this embodiment.

The application LSI 601 includes a system CPU (Central Processing Unit)701, an SDRAM (Synchronous Dynamic Random Access Memory) interface 702,a multimedia block 703, a DMAC (Direct Memory Access Controller) 704, amemory 705, a card interface 711, a timer 712, a serial interface 713,other functional blocks 714, a DSP (Digital Signal Processor) 721, aserial interface 722 for baseband LSI communication, an audio dataprocessing block 723, a parallel serial converter 724, and a switchcircuit 725. These components are connected by buses. This applicationLSI 601 may be used in both of the A-vocoder system and the C-vocodersystem.

The system CPU 701 controls each block arranged in the application LSI601, and the battery 605, the power IC 606, the camera unit 608, theoperation input unit 609, the display unit 607, the audio LSI 610, themicrophone 611, the speaker 612 and the like shown in FIG. 2. That is,the application LSI 601 controls the whole system. Further, theapplication LSI 601 controls various applications including videoreproduction, music reproduction, 2D/3D graphic processing, cameras, SDcard control, power supply control, memories, input/output, anddisplays, for example. Thus, processing according to the application isexecuted.

The SDRAM interface 702 is an interface with an SDRAM installed in theelectronic device 600. The multimedia block 703 performs a multimediafunction, e.g., image reproduction and music reproduction. The DMAC 704controls direct memory access. The memory 705 stores control programs,various settings and the like required to operate the application LSI601.

The card interface 711 is an interface with a card. The serial interface713 is an interface in a serial communication. The DSP 721 performspredetermined data processing (vocoding) on digital audio data. Forexample, the DSP 721 converts the AMR data into the PCM data dependingon its application. The DSP 721 executes effect processing includingsampling rate conversion, noise cancelling, and echo cancelling on theconverted PCM data.

The serial interface 722 for baseband LSI communication is an interfacefor performing serial communication with the baseband LSI 602. That is,the serial interface 722 transmits data to the baseband LSI 602 andreceives data from the baseband LSI 602. The audio data processing block723 performs mixer processing, filter processing, volume adjustmentprocessing and the like on the audio data. The DSP 721 and the audiodata processing block 723 are blocks for performing the vocoder. Theparallel serial converter 724 performs processing for converting theparallel data and the serial data.

The switch circuit 725 is one of the features of the application LSI 601according to this embodiment, and is a switch circuit that performsswitching processing. The data transmission between the application LSI601 and the baseband LSI 602 is performed through the switch circuit725. In the similar way, the data transmission between the applicationLSI 601 and the audio LSI 610 is performed through the switch circuit725. The switch circuit 725 switches connection to the baseband LSI 602and the connection to the audio LSI 610. In short, the switch circuit725 installed in the application LSI connects the data path between theaudio LSI 610 and the baseband LSI 602.

Now, with reference to FIGS. 8 to 10, the data flow among the basebandLSI 602, the application LSI 601, and the audio LSI 610 will bedescribed. FIG. 8 is a diagram showing a data flow when all the vocoderprocessing is performed in the application LSI 601. FIG. 9 is a diagramshowing a data flow when telephone call or recording is performed. FIG.10 is a diagram showing a data flow when guidance reproduction isperformed which does not involve telephone call. Further, FIGS. 8 to 10all show the C-vocoder system.

In FIGS. 8 to 10, BBIF2_TXD indicates a data terminal for uplink,BBIF2_RXD indicates a data terminal for downlink, BBIF2_SYNC indicates async terminal for PCM communication, BBIF2_SCK indicates a bit clockterminal for PCM communication, FSIBOSLD indicates a data terminal fordownlink, FSIBISLD indicates a data terminal for uplink, FSIBOLRindicates a sync terminal for PCM communication, and FSIBOBT indicates abit clock terminal for PCM communication.

As shown in FIGS. 8 to 10, the switch circuit 725 is included in theapplication LSI 601. The switch circuit 725 is controlled by GPIO outputfrom the system CPU 701. Thus, the GPIO output from the system CPU 701serves as a control signal for switching the switch operation by theswitch circuit 725.

When the application LSI 601 performs all the vocoder processing, asshown in FIG. 8, the audio data (e.g., AMR data) from the baseband LSI602 is transmitted to the serial interface 722 through the switchcircuit 725. Then, the audio data input to the serial interface 722 isdecoded by the DSP 721 of the application LSI 601. Then, the audio data(e.g., PCM data) that is decoded is output to the audio LSI 610. Theaudio LSI 610 D/A converts the input audio data, and outputs theconverted data to the speaker 612.

Further, the voice detected by the microphone 611 is converted into thedigital signal (e.g., PCM data) by the audio LSI 610. Then, the audiodata from the audio LSI 610 is input to the application LSI 601. The DSP721 or the like of the application LSI 601 performs decoding and effectprocessing on the input audio data. Then, the decoded audio data isoutput to the baseband LSI 602 through the switch circuit 725. In thisway, when the vocoder is not executed by the baseband LSI 602, theswitch circuit 725 operates so that data communication is not performedbetween the baseband LSI 602 and the audio LSI 610. Thus, the data pathbetween the baseband LSI 602 and the audio LSI 610 is interrupted.Accordingly, data communication is performed between the baseband LSI602 and the audio LSI 610 through the processing of the application LSI601.

When telephone call or recording is executed, as shown in FIG. 9, thedigital data from the audio LSI 610 is sent to the baseband LSI 602 andthe application LSI 601. The application LSI 601 executes vocoderprocessing required for recording. Specifically, the DSP 721 decodes theaudio data input from the audio LSI 610. The application LSI 601 storesthe decoded audio data in the SDRAM or the memory 705 of the NOR flash.On the other hand, when telephone call is made, the audio data from theaudio LSI 610 is encoded by the baseband LSI 602. That is, the basebandLSI 602 performs vocoder processing required to perform telephone call.The audio data from the baseband LSI 602 is sent to the RF subsystem603, and telephone call is performed. Further, the audio data receivedby the RF subsystem 603 is decoded by the baseband LSI 602. The audiodata decoded by the baseband LSI 602 is sent to the audio LSI 610. Theaudio LSI 610 D/A converts the audio data to output the converted datato the speaker 612. The speaker 612 reproduces the voice.

Further, when guidance such as an answering machine message isreproduced, as shown in FIG. 10, the audio data output from theapplication LSI 601 is input to the baseband LSI 602 and the audio LSI610. Then, the baseband LSI 602 performs vocoder to encode the audiodata. The audio data output from the baseband LSI 602 is input to theapplication LSI 601. The data output from the audio LSI 610 is input tothe application LSI 601. In this way, when the C-vocoder is executed,the switch circuit 725 is operated so that data communication isperformed between the baseband LSI 602 and the audio LSI 610 accordingto the function that is used.

As described above, when the vocoder processing is performed by thebaseband LSI 602, as shown in FIGS. 9 and 10, the switch circuit 725switches the data path so that data communication is performed betweenthe baseband LSI 602 and the audio LSI 610. In this state, the dataoutput from the baseband LSI 602 is directly sent to the audio LSI 610through the switch circuit 725, and the data output from the audio LSI610 is directly sent to the baseband LSI 602 through the switch circuit725.

On the other hand, when the application LSI 601 performs all the vocoderprocessing, as shown in FIG. 8, the switch circuit 725 switches the datapath so that data communication is not performed between the basebandLSI 602 and the audio LSI 610. In this case, the data output from thebaseband LSI 602 to the application LSI 601 is subjected to vocoderprocessing by the DSP 721 and the audio data processing block 723, andthen output to the audio LSI 610. Further, the data output from theaudio LSI 610 to the application LSI 601 is subjected to vocoderprocessing by the DSP 721 and the audio data processing block 723, andthen output to the baseband LSI 602.

As described above, the switch circuit 725 that switches the data pathis provided in the application LSI 601. Accordingly, the board 630 canbe commonly used by the A-vocoder system and the C-vocoder system. Inshort, the application LSI 601 may be mounted on the same board 630 inboth systems. For example, when the application LSI 601 is mounted onthe C-vocoder system of the method 2 which requires switch of the datapath, switching is performed according to the scene, as shown in FIGS. 8to 10.

When only the application LSI 601 executes vocoding, the switch circuit725 interrupts the data path between the audio LSI 610 and the basebandLSI 602. When the baseband LSI 602 executes vocoding, the switch circuit725 connects the data path between the audio LSI 610 and the basebandLSI 602. The switch circuit 725 operates to switch the data pathaccording to the element of the vocoding that is executed. The operationof the switch circuit 725 is controlled by the GPIO output from thesystem CPU 701.

On the other hand, when the application LSI 601 is installed in theA-vocoder system, there is no case that the baseband LSI 602 executesvocoder. Thus, the baseband LSI 602 and the audio LSI 610 may be alwaysseparated from each other. In short, when the application LSI 601 isinstalled in the A-vocoder system, the switch circuit 725 alwaysinterrupts the data path between the audio LSI 610 and the baseband LSI602. The data path in this case is similar to that shown in FIG. 8.

According to this configuration, there is no need to mount a logiccircuit that switches the data path on the board 630. Accordingly, it ispossible to commonly use the board 630. In short, there is no need tonewly design different boards 630 for the A-vocoder and the C-vocoder.Further, it is possible to reduce the number of elements mounted on theboard 630, thereby being able to reduce manufacturing cost and achievecompactness.

Further, it may be possible that different baseband LSIs 602 are usedand the elements of the vocoder to be executed in the baseband LSIs 602are different depending on the type of the mobile phone. Since differentcontrols are required depending on the baseband LSI 602 to be used, itis difficult to commonly use the switch circuit. However, by includingthe switch circuit 725 in the application LSI 601 as in this embodiment,the board 630 can be commonly used.

In particular, it is possible to commonly use the board 603, which isrequired in the transition period from the C-vocoder to the A-vocoder.Further, depending on the type of the mobile phone, the application LSI601 and the baseband LSI 602 may be manufactured by differentmanufacturers of semiconductor devices. In this case, it is desired forthe manufacturer of the audio LSIs 610 to manufacture the applicationLSIs 601 that can be used in any type of baseband LSIs 602. When thebaseband LSI 602 executes vocoder, parameters of noise cancelling, echocancelling, and the like are the technical know-how, and manufactures ofthe baseband LSIs 602 and mobile phones do not want to disclose them.Even in such a case, it is possible to use the baseband LSI 602 withoutany modification in design by using the application LSI 601 according tothis embodiment. In short, it is possible to commonly use the board 630and the application LSI 601 regardless of the type of the baseband LSI602, thereby improving convenience.

Further, since the application LSI 601 executes vocoding, voice qualitycan be improved. More specifically, since the application LSI 601 havinghigher processing ability than the baseband LSI 602 executes vocoding,it is possible to achieve high-load processing, thereby being able toremove noise or echo more efficiently. Thus, voice quality can beimproved. For example, in the case of high-end mobile phones,higher-load processing needs to be performed. In this case, it ispossible to cause the application LSI 601 with high processing abilityto execute the processing. Further, in the case of low-end mobilephones, the load is not high, and thus the baseband LSI 602 may performa part of the vocoder processing.

Further, by stopping power supply to a part of the blocks according tothe processing, power consumption can be reduced. This point will bedescribed below with reference to FIGS. 11 to 13. FIGS. 11 to 13 aredrawings schematically showing a data flow in the application LSI 601,and the blocks to which power is supplied are surrounded by a dottedline. In other words, power supply to each block outside the dottedframe is stopped.

When only the baseband LSI 602 performs vocoding in the C-vocodersystem, power may be supplied only to the switch circuit 725 as shown inFIG. 11. That is, since processing is not performed in the applicationLSI 601, it is possible to stop power supply to almost all the blocks ofthe application LSI 601. Thus, power consumption can be reduced. In thiscase, the PCM data is generated by the baseband LSI 602. Then, the PCMdata communication is performed between the baseband LSI 602 and theaudio LSI 610 through the switch circuit 725 included in the applicationLSI 601. As a matter of course, the process of the PCM data (noisecancelling and the like) may be performed in the baseband LSI 602.

On the other hand, when the application LSI 601 executes vocoding, powermay be supplied only to the blocks required to perform the processing.For example, as shown in FIG. 12, power is supplied only to the areasurrounded by the dotted line. FIG. 12 shows an example in which theapplication LSI 601 installed in the C-vocoder system performs effectprocessing. In this way, power supply to a part of the blocks in theapplication LSI 601 can be stopped, thereby being able to reduce powerconsumption. Specifically, power is supplied to the DSP 721, the serialinterface 722, the audio data processing block 723, the parallel serialconverter 724, and the switch circuit 725, and power supply to the otherblocks including the system CPU 701 is stopped. In this way, powerconsumption can be reduced.

Note that, in FIG. 12, the baseband LSI 602 decodes audio data toconvert the audio data into PCM data. At this time, the switch circuit725 interrupts the data path between the baseband LSI 602 and the audioLSI 610. The application LSI 601 transmits data to the baseband LSI 602or receives data from the baseband LSI 602. The serial interface 722serves as an interface of data transmission to the baseband LSI 602 anddata reception from the baseband LSI 602. The baseband LSI 602 convertsthe AMR data into the PCM data. Then, the DSP 721 of the application LSI601 processes the PCM data. The DSP 721 performs sampling rateconversion, noise cancelling, and echo cancelling, for example. Theaudio data on which effect processing is performed is output to theaudio LSI 610 through the switch circuit 725.

On the other hand, the PCM data from the audio LSI 610 is output to theapplication LSI 601. The DSP 721 of the application LSI 601 processesthe PCM data. The PCM data that is processed is output to the basebandLSI 602 using the serial interface 722 as an interface. Then thebaseband LSI 602 encodes the PCM data.

FIG. 13 is a diagram showing a data flow of the application LSI 601installed in the A-vocoder system. In the A-vocoder system, theapplication LSI 601 executes all the elements of vocoding, which meansthe baseband LSI 602 does not execute vocoding. Thus, the baseband LSI602 outputs the audio data (hereinafter referred to as AMR data) that isencoded to the application LSI 601. At this time, the switch circuit 725interrupts the data path between the baseband LSI 602 and the audio LSI610. The serial interface 722 serves as an interface of datatransmission to the baseband LSI 602 and data reception from thebaseband LSI 602.

Then, the DSP 721 of the application LSI 601 decodes the AMR data to thePCM data. Further, the DSP 721 executes the process of the PCM data,e.g., vocoding such as sampling rate conversion, noise cancelling. Then,the application LSI 601 outputs the audio data to the audio LSI 610through the switch circuit 725.

In FIGS. 12 and 13, power is supplied only to the blocks surrounded bythe dotted line. In short, power supply to the blocks which do not havea relation with vocoding is stopped. In this way, a part of power supplyis stopped depending on the vocoding that is executed. In short, powersupply to a part of the application LSI 601 is stopped depending on theconnection state of the data path. Accordingly, it is possible tooperate only the blocks which are required for the processing, therebybeing able to reduce power consumption. For example, when the vocoder isexecuted, power supply to the blocks which are not required for thevocoder is stopped, thereby being able to reduce power consumption.

When the switch circuit 725 performs the switching operation, the systemCPU 701 is turned on, and the system CPU 701 executes switch processingof the switch circuit 725. After the switching processing is completed,power supply to the system CPU 701 is stopped. When the switching isrequired again, the system CPU 701 executes switch processing of theswitch after power supply to the system CPU 701 is restarted.

Further, since the control is intensively performed in the applicationLSI 601, it is possible to easily switch the path. Further, in order toavoid noise due to the switch of the path, the application LSI 601 mayhave a mute function. FIG. 14 shows a configuration example of a mutecircuit installed in the application LSI 601. The mute circuit includesa frequency divider 801, a shift register 802, a shift register 803, anda selector 804, and is installed inside the application LSI 601.

For example, the frequency divider 801 generates a SYNC signal of apredetermined frequency (8 kHz). The shift registers 802 and 803 shiftthe audio data to a lower-order bit in synchronization with the SYNCsignal. For example, in the case of 16-bit audio data, only thehigher-order bit is audible and the lower-order bit is not audible forpeople. Accordingly, the mute function can be achieved by shifting theaudio data to the lower-order bit.

As shown in FIG. 14, when the data of the output A is switched to thedata of the output B while the voice call is made, noise is generated.In order to reduce the noise, the data of the output A and the output Bare temporarily muted before and after the data is switched, and theselector 804 switches the data in the silent state. After the data isswitched, the shift registers 802 and 803 execute processing to increasethe volume to the original audio level.

The mute circuit operates when the switch circuit 725 performs theswitching operation. The system CPU 701 mutes the voice reproduced fromthe speaker 612 according to the timing that the switch circuit 725performs switching. For example, the control is performed in such a waythat the voice is not reproduced in a period in which switching isperformed in the application LSI 601, and the mute state is cancelledupon completion of the switching. The control of the mute function isperformed by the control signal output from the system CPU 701 as issimilar to the GPIO that switches the switch circuit 725.

In this way, it is possible to efficiently remove the noise with asimple configuration. Further, the switch circuit 725 that performsswitching is installed in the application LSI 601 and the mute circuitis installed in the application LSI 601, whereby it is possible toperform control in a simple manner. In short, it is not required tooutput the signal that controls the mute state from the application LSI601 to the baseband LSI 602, whereby it is possible to perform controlinside the application LSI in a simple manner.

The present invention is not limited to the embodiments stated above,but may be changed as appropriate without departing from the spirit ofthe present invention.

While the invention has been described in terms of several embodiments,those skilled in the art will recognize that the invention can bepracticed with various modifications within the spirit and scope of theappended claims and the invention is not limited to the examplesdescribed above.

Further, the scope of the claims is not limited by the embodimentsdescribed above.

Furthermore, it is noted that, Applicant's intent is to encompassequivalents of all claim elements, even if amended later duringprosecution.

1-12. (canceled)
 13. A radio communication device comprising: anantenna; a radio frequency circuit configured to receive a receptionsignal through the antenna; a baseband processor configured to performbaseband processing and execute vocoding; an audio processor configuredto execute a D/A conversion and an A/D conversion on audio data andexecute vocoding; and an application processor, configured to execute anapplication program, including a switch circuit configured to: connect afirst data path between the audio processor and the applicationprocessor when the application processor executes vocoding, and connecta second data path between the audio processor and the basebandprocessor when the baseband processor executes vocoding.
 14. The radiocommunication device according to claim 13, wherein the switch circuitselectively disconnects the second data path between the audio processorand the baseband processor when only the application processor executesvocoding.
 15. The radio communication device according to claim 13,wherein the baseband processor is configured to connect to a Long TermEvolution (LTE) network.
 16. The radio communication device according toclaim 13, further comprising: a speaker configured to reproduce audiodata that is D/A converted by the audio processor.
 17. The radiocommunication device according to claim 16, wherein the applicationprocessor is configured to mute the audio data that is reproduced fromthe speaker according to a timing of switching by the switch circuit.